Model experiment of uneven frost heave of airport pavement structure on coarse-grained soils foundation

Sample soil was prepared with natural gravel soil and surface silt from Guoluo Airport in China in this study. An original laboratory experiment model of uneven frost heave of airport pavement structure (UFHAPS) was designed and established, whose experimental apparatus' accuracy and precision were demonstrated by calibration. A test of external water infiltration, an indoor model experiment and a field monitoring experiment of the UFHAPS were conducted, then, the laboratory experiment model's reliability and applicability were verified by the results of the field monitoring experiment of UFHAPS. Experimental results showed that the model experiment intuitively simulated the phenomenon of faulting of slab ends between runway and its shoulder, clarifying the causes and mechanism. The effect of external water infiltration on UFHAPS was obtained, especially moisture field redistribution suffered the most impact of external water infiltration. The phenomenon of UFHAPS was a result of the coupling of temperature field and moisture field inside airport pavement structure. Moisture migration and accumulation were affected by the cooling rate and temperature gradient, in turn, the moisture field redistribution also affected the delivery of temperature. In summary, the basic laws of temperature field, moisture field and displacement field, especially the laws of moisture-heat coupling were systematically revealed.